Capturing anaphylaxis through medical records: Are ICD and CPT codes sufficient?

Area of Science:

• Medical Informatics
• Allergy and Immunology
• Health Services Research

Background:

• Effective identification of anaphylaxis cases is essential for clinical practice and research.
• Provider knowledge deficits in diagnosing and treating anaphylaxis impact case identification.
• Reimbursement codes, including International Classification of Diseases (ICD) and Current Procedural Terminology (CPT), are utilized for detecting anaphylaxis in administrative data.

Purpose of the Study:

• To evaluate the efficacy of current reimbursement codes in detecting anaphylaxis cases.
• To identify challenges in using administrative claims data for anaphylaxis surveillance.
• To explore potential improvements in anaphylaxis case detection through coding systems.

Main Methods:

• A review of recent and relevant literature concerning anaphylaxis, provider knowledge, and various coding systems (ICD, CPT, HCPCS, E-codes).
• Analysis of the positive predictive value (PPV) of different reimbursement codes for identifying anaphylaxis events.

Main Results:

• Anaphylactic shock-specific ICD codes demonstrated a PPV of 52%–53% compared to physician chart review.
• Combining ICD codes with anaphylaxis symptom-specific ICD, CPT, HCPCS, and E-codes improved PPV to 63%–67.3%.
• Challenges include inaccurate provider recognition, underreporting, and difficulties in cause identification.

Conclusions:

• Systematic educational investments are needed to enhance provider diagnosis and treatment of anaphylaxis.
• Current ICD codes for anaphylactic shock have suboptimal PPV for administrative claims databases.
• Future ICD-11 reclassification holds promise for improving anaphylaxis detection via reimbursement codes, though limitations of inaccurate diagnoses and underreporting persist.